docs: def plate_exchanger_identifier(self):
          '''Method to create an identifying string in format 'L' + wavelength + 
          'A' + amplitude + 'B' + chevron angle-chevron angle. Wavelength and 
          amplitude are specified in units of mm and rounded to two decimal places.
          '''
          s = ('L' + str(round(self.wavelength*1000, 2))
               + 'A' + str(round(self.amplitude*1000, 2))
               + 'B' + '-'.join([str(i) for i in self.chevron_angles]))
          return s